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Objective Procedures Results Conclusions Investigate the tolerance, stability, and efficacy of topical 0.1% and 1% atropine in cats.Six cats underwent two trials separated by a 2‐week washout period. One drop of artificial tears was placed in one randomly selected eye (control), and one drop of either 0.1% atropine (Trial I) or 1% atropine (Trial II) was placed in the other eye. Immediate adverse effects were recorded for severity (0–3) and duration (seconds). Horizontal pupil diameter (HPD), pupillary light reflexes (PLRs), intraocular pressure (IOP), Schirmer tear test‐1 (STT‐1), and heart rate (HR) were monitored at baseline then 8 h post‐administration. PLRs were assessed for a total of 72 h. Stability was assessed weekly for 1 month in room temperature and refrigerated conditions, evaluating solution clarity, pH, and drug concentrations.Adverse effects had a significantly lower severity score and shorter duration with 0.1% versus 1% atropine (severity 1.2 ± 0.4 vs. 2.5 ± 0.5, p = .010; duration 107.5 ± 53.3 vs. 293.3 ± 106.5 s, p = .009). HPD was significantly greater than baseline measurements as early as 40 min for both atropine formulations. Pupils were non‐responsive for a significantly shorter duration with 0.1% versus 1% atropine (median 7 h vs. 47.5 h, p = .031). Compared with control eyes, IOP was significantly elevated by 1% atropine (p = .021) but not 0.1% atropine (p = .502). No significant differences were noted in STT‐1 and HR measurements. Both solutions were stable in room temperature and refrigerated conditions for 1 month.Diluted 0.1% atropine was stable and better tolerated by cats, offering a potential alternative to feline patients that experience adverse effects from topical 1% atropine. [ABSTRACT FROM AUTHOR]

Retinitis pigmentosa (RP) is a heterogeneous inherited retinal disorder. Mutations in KIZ cause autosomal recessive (AR) RP. We aimed to characterize the genotype, expression pattern, and phenotype in a large cohort of KIZ cases. Sanger and whole exome sequencing were used to identify the KIZ variants. Medical records were reviewed and analyzed. Thirty-one patients with biallelic KIZ mutations were identified: 28 homozygous for c.226C>T (p.R76*), 2 compound heterozygous for p.R76* and c.3G>A (p.M1?), and one homozygous for c.247C>T (p.R83*). c.226C>T is a founder mutation among patients of Jewish descent. The clinical parameters were less severe in KIZ compared to DHDDS and FAM161A cases. RT-PCR analysis in fibroblast cells revealed the presence of four different transcripts in both WT and mutant samples with a lower percentage of the WT transcript in patients. Sequence analysis identified an exonic sequence enhancer (ESE) that includes the c.226 position which is affected by the mutation. KIZ mutations are an uncommon cause of IRD worldwide but are not rare among Ashkenazi Jews. Our data indicate that p.R76* affect an ESE which in turn results in the pronounced skipping of exon 3. Therefore, RNA-based therapies might show low efficacy since the mutant transcripts are spliced. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusions Assess aqueous tear production when measured with the dogs' eyelids open or closed.Thirty healthy dogs (15 Shih Tzus, 15 Labrador retrievers) were recruited. With the order of testing randomized for each dog, two sessions (separated by 30 min) of STT‐1 testing were performed with the dogs' eyelids closed or open. Schirmer strip wetness (every 10 s for 60 s) and number of time(s) the strip dislodged during testing were recorded in each eye. Preferred STT‐1 method was surveyed via a global Listserv of the veterinary ophthalmology community.STT‐1 values were significantly higher in closed versus open eyes in Shih Tzus (18.6 ± 2.7 mm/min vs. 16.3 ± 2.5 mm/min; p = .002) and Labrador retrievers (21.6 ± 2.9 mm/min vs. 17.8 ± 3.2 mm/min, p < .001), findings that were also significant at times <60 s for either breed (p ≤ .004). Schirmer strips dislodged from six dogs with open eyelids and no dogs with closed eyelids. Maximal STT‐1 difference with closed versus open eyelids was 13 mm/min in Labrador retrievers and 7 mm/min in Shih Tzus. Survey results from 275 veterinarians showed STT‐1 performed with “closed eyelids” (38.5%), “open eyelids” (26.9%), or “never paid attention, sometimes closed, sometimes open” (34.6%).Eyelids status (closed or open) during STT‐1 testing had a significant impact on aqueous tear secretion in brachycephalic and nonbrachycephalic dogs, highlighting the importance of consistency when repeating STT‐1 in a canine patient. STT‐1 differences are likely due to sustained reflex tearing throughout the test duration when the dogs' eyelids are closed. [ABSTRACT FROM AUTHOR]

Rats are a commonly used animal model for the study of the pathogenesis and novel treatments of glaucoma, which is induced experimentally using invasive, painful procedures. Peribulbar anaesthesia (PBA) is frequently used in people and domestic animals prior to ophthalmic surgeries to provide excellent perioperative analgesia. Our goal was to develop a PBA technique adapted to rat anatomy, improving the welfare of animals used as a model for glaucoma. Eighteen rat cadavers (n = 36 eyes) were used to establish the optimal needle insertion location. Five injection techniques using 0.1 mL/100 g lidocaine 2% and a contrast agent (1:1 volume ratio) were compared via computed tomography (CT). CT images were scored for injectate distribution at four locations: extraconal, intraconal, around the optic nerve and at the orbital fissure (scale 0–8, where 0 = none and 8 = excellent). Median scores using the dorso-medial-75° (5; range 2–6) and medial-canthus (4.5; range 2–8) injection techniques were not different from the dorso-medial-45° (4; range 3–6) technique and were higher (better distribution) compared with mid-ventral (3; range 2–5) and ventro-lateral (2; range 1–3) techniques. The two superior techniques were used in two experimental rats (n = 4 eyes) to determine the volume of bupivacaine 0.5% necessary to affect corneal touch threshold (CTT) and periocular skin sensitivity (PSS). A volume of 0.05 mL/100 g decreased CTT and PSS for several hours, while a larger volume produced excessively long effects. Dorso-medial-75° or medial-canthus PBA using 0.05 mL/100 g bupivacaine are likely to provide ocular and periocular analgesia in rats, with minor transient adverse effects. [ABSTRACT FROM AUTHOR]

PurposeA form of retinal degeneration suspected to be hereditary was discovered in a family of Bengal cats. A breeding colony was established to characterize disease progression clinically, electrophysiologically, and morphologically, and to investigate the mode of inheritance.MethodsAffected and related cats were donated by owners for breeding trials and pedigree analysis. Kittens from test and complementation breedings underwent ophthalmic and neuro-ophthalmic examinations and ERG, and globes were evaluated using light microscopy.ResultsPedigree analysis, along with test and complementation breedings, indicated autosomal recessive inheritance and suggested that this disease is nonallelic to a retinal degeneration found in Persian cats. Mutation analysis confirmed the disease is not caused by CEP290 or CRX variants found predominantly in Abyssinian and Siamese cats. Ophthalmoscopic signs of retinal degeneration were noted at 9 weeks of age and became more noticeable over the next 4 months. Visual deficits were behaviorally evident by 1 year of age. Electroretinogram demonstrated reduced rod and cone function at 7 and 9 weeks of age, respectively. Rod responses were mostly extinguished at 14 weeks of age; cone responses were minimal by 26 weeks. Histologic degeneration was first observed at 8 weeks, evidenced by reduced photoreceptor numbers, then rapid deterioration of the photoreceptor layer and, subsequently, severe outer retinal degeneration.ConclusionsA recessively inherited primary photoreceptor degeneration was characterized in the Bengal cat. The disease is characterized by early onset, with histologic, ophthalmoscopic, and electrophysiological signs evident by 2 months of age, and rapid progression to blindness.

Purpose: Assess the refractive states of donkeys and goats. Methods: Forty‐two donkeys and 28 goats were enrolled. The mean ± SD ages were 7.68 ± 7.33 years for donkeys and 4.26 ± 2.33 years for goats. Seven donkeys and one goat were <6 months old. Retinoscopy was performed in alert animals, following cycloplegia in goats but not in donkeys. Normality was determined using the Kolmogorov–Smirnov test. The two primary meridians and two eyes were compared using Pearson's correlation and paired Student's t–tests. The association between refractive states and age was examined using one‐way ANOVA in donkeys and a paired Student's t‐test in goats. One‐sample t‐tests were conducted to assess if the refractive error distributions were significantly different from "0". Results: The mean ± SD spherical equivalent (SE) refractive errors of the right and left donkey eyes were −0.80 ± 1.03 D and −0.35 ± 0.95 D, respectively. The majority (86%) of the donkeys had an astigmatic refraction and eight (19%) had anisometropia. The mean SE refractive errors of the right and left goat eyes were −0.15 ± 1.1 D and −0.18 ± 1.2 D, respectively. The majority (54%) of the goat eyes had an astigmatic refraction and five (18%) had anisometropia. The right and left eye SE refractive errors were positively correlated in both species (both p =.9). Age was not correlated with refractive error in both donkeys (p =.09) and goats (p =.6). Conclusions: Both goats and donkeys are emmetropic. [ABSTRACT FROM AUTHOR]

Objective: Electroretinography (ERG) is used prior to cataract removal surgery to assess retinal function. We aimed to replicate and improve upon previous studies by performing a full ECVO protocol and by examining the retina post‐surgery in all patients. Animals studied: One hundred twenty‐seven eyes from 67 dogs were included in the study. Procedures: A full ECVO protocol electroretinography, which includes extensive rod and cone analysis, was performed on all dogs presenting for cataract surgery. Results: Our main findings were that amplitudes, but not implicit times of rod responses decreased with advanced cataracts. Amplitudes of the single flash rod and rod flicker responses were significantly lower in eyes with mature cataracts, and the former also decreased in hypermature cataracts. Cone flicker amplitude responses were also significantly lower in eyes with mature and hypermature cataracts. However, mixed single flash rod‐cone and cone responses, with the exception of the mixed rod‐cone a‐wave amplitude in eyes with hypermature cataracts, were unaffected by cataract stage. The b‐wave amplitude of the scotopic, mixed rod‐cone, and photopic cone responses were affected by age and decreased by an average of 2.9, 7.5, and 1.5 μV/year, retrospectively (p < 0.01). Conclusions: Lower ERG amplitudes in canine cataract patients may result from aging or the presence of advanced cataracts and may not indicate the presence of retinal disease. [ABSTRACT FROM AUTHOR]